AWS RDS MySQL Read Replicas Data Sync time

2019-09-24 09:30发布

问题:

We have and architecture of a scalable web application on AWS and utilized AWS RDS MySQL. They say you have to create 2 Slave Read-Replicas for your MySQL Master db instance. Using this, the master DB will synchronize your data whenever it finds a change (in its master instance) across all of the read replicas. Your application has to split Read and Write operations so that All the Read Requests goes to Read-Replicas (Via a load-balancer or DNS) and write requests\ops goes to the master db.

Now my question is if a user visits a page which has a write operation, he does the operation and click to a page where a Read Operation is required of that new entered data. How much the Master db will take to sync with slave read-replicas so that the user can successfully see the read-operation result (i.e. the newly created record) on the very next page.

回答1:

RDS MySQL Read Replica lag is influenced by a number of factors including the load on both the primary and secondary instances, the amount of data being replicated, the number of replicas, if they are within the same region or cross-region, etc. Lag can stretch to seconds or minutes, though typically it is under one minute.

For low-lag (10s of milliseconds) read replicas in a MySQL-compatible database you can use Amazon Aurora.